A visible difference in shoulder height, where one side appears higher than the other, is a common physical observation that frequently prompts people to seek answers. This asymmetry is a sign that the body’s structural and muscular systems are compensating for an imbalance somewhere along the kinetic chain. While such a finding can initially cause concern, the reasons for a high shoulder are generally categorized as either functional, meaning they are due to habit and muscle adaptation, or structural, meaning they are related to the underlying skeletal alignment. Understanding this distinction is the first step toward determining the appropriate course of action.
Functional Causes: Posture and Muscle Imbalances
The most frequent causes for an elevated shoulder are rooted in daily habits that lead to asymmetrical muscle tension and weakness. This is often described as a functional asymmetry because the underlying bones are correctly sized, but the soft tissues have adapted to an uneven load. The primary muscles involved in pulling a shoulder upward are the upper trapezius and the levator scapulae, and chronic tension in these muscles on one side can visibly raise that shoulder.
Activities that require prolonged, one-sided engagement cause these muscles to become chronically shortened and overactive. For example, consistently carrying a heavy messenger bag or purse on the same shoulder forces the upper trapezius to contract continuously. Similarly, cradling a phone between the ear and the elevated shoulder creates sustained contraction in the levator scapulae.
Poor workplace ergonomics are another significant contributor to this muscle imbalance, particularly for those who spend long hours seated at a desk. An improperly positioned computer monitor or a chair with an armrest that is too high can maintain the elevated shoulder posture. Over time, this chronic muscle shortening is compounded by weakness in the opposing muscles, such as the lower trapezius and serratus anterior, which stabilize the shoulder blade. The body develops a predictable pattern of tightness and weakness, resulting in the visually uneven shoulder alignment.
Structural Causes: Skeletal Conditions
In contrast to functional issues, structural causes of shoulder asymmetry involve a fixed difference in the bony framework that cannot be corrected by posture alone. These conditions are less common but require specialized medical attention as they involve the spine, pelvis, or shoulder girdle itself. The most recognized structural cause is scoliosis, which is a three-dimensional lateral curvature and rotation of the spine.
When the spine curves laterally, the vertebrae rotate, forcing the rib cage to become asymmetrical and pushing one shoulder blade to be more prominent and elevated. Shoulder height difference is a classic visual indicator of scoliosis, especially when the spinal curve is located in the thoracic region.
Leg Length Discrepancy (LLD)
An underlying structural issue in the lower body can also lead to shoulder height differences, such as a true leg length discrepancy (LLD). If one leg bone is anatomically shorter than the other, it causes the pelvis to tilt. To keep the head level, the spine compensates for this pelvic obliquity by developing a compensatory curve. This chain reaction then manifests as one shoulder being visibly higher, often on the side corresponding to the shorter leg.
Previous Injury
A previous injury, such as a fractured clavicle (collarbone) that healed with significant shortening (malunion), can permanently alter the shoulder girdle’s geometry. This causes the shoulder on the affected side to sit in a different position relative to the unaffected side.
Professional Assessment and Management
Determining whether the high shoulder is functional or structural requires a thorough physical examination by a healthcare professional, such as a physical therapist or a physician. The assessment begins with visual observation of the standing posture, followed by range of motion tests and palpation to identify areas of muscle tightness and weakness. A key diagnostic step is to see if the asymmetry corrects itself when the patient performs certain movements or changes position, which suggests a functional cause.
If a structural issue like scoliosis or LLD is suspected, imaging studies are used to confirm the diagnosis and quantify the severity. A standing full-spine X-ray is the gold standard, as it allows the clinician to measure the Cobb angle for spinal curvature and precisely measure the difference in leg length. In cases of LLD, a simple test involves placing a lift under the shorter leg to see if the spinal curvature and shoulder height normalize, confirming that the asymmetry is compensatory.
Management strategies are directly tailored to the identified cause.
Functional Asymmetry Treatment
For functional asymmetry, treatment focuses on a targeted program of stretching and strengthening. This involves stretching the tight, overactive muscles (upper trapezius and levator scapulae) and strengthening the weak, stabilizing muscles (lower trapezius and serratus anterior). This is paired with practical ergonomic adjustments to the workspace to eliminate the habitual cause of the imbalance.
Structural Issues Treatment
For structural issues, management may involve specialized interventions. This includes an orthotic shoe lift to compensate for a leg length discrepancy greater than 5 millimeters. For scoliosis, management involves bracing and monitoring to prevent progression of the spinal curve.